Catalyst 2960 Switch Software Configuration Guide, 12.2(25)SED

Configuring RMON

This chapter describes how to configure Remote Network Monitoring (RMON) on the Catalyst 2960 switch.

RMON is a standard monitoring specification that defines a set of statistics and functions that can be exchanged between RMON-compliant console systems and network probes. RMON provides you with comprehensive network-fault diagnosis, planning, and performance-tuning information.

Note For complete syntax and usage information for the commands used in this chapter, see the "System Management Commands" section in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2.

This chapter consists of these sections:

•Understanding RMON

•Configuring RMON

•Displaying RMON Status

Understanding RMON

RMON is an Internet Engineering Task Force (IETF) standard monitoring specification that allows various network agents and console systems to exchange network monitoring data. You can use the RMON feature with the Simple Network Management Protocol (SNMP) agent in the switch to monitor all the traffic flowing among switches on all connected LAN segments as shown in Figure 25-1.

Figure 25-1 Remote Monitoring Example

The switch supports these RMON groups (defined in RFC 1757):

•Statistics (RMON group 1)—Collects Ethernet statistics (including Fast Ethernet and Gigabit Ethernet statistics, depending on the switch type and supported interfaces) on an interface.

•History (RMON group 2)—Collects a history group of statistics on Ethernet ports (including Fast Ethernet and Gigabit Ethernet statistics, depending on the switch type and supported interfaces) for a specified polling interval.

•Alarm (RMON group 3)—Monitors a specific management information base (MIB) object for a specified interval, triggers an alarm at a specified value (rising threshold), and resets the alarm at another value (falling threshold). Alarms can be used with events; the alarm triggers an event, which can generate a log entry or an SNMP trap.

•Event (RMON group 9)—Specifies the action to take when an event is triggered by an alarm. The action can be to generate a log entry or an SNMP trap.

Because switches supported by this software release use hardware counters for RMON data processing, the monitoring is more efficient, and little processing power is required.

Configuring RMON

These sections contain this configuration information:

•Default RMON Configuration

•Configuring RMON Alarms and Events (required)

•Collecting Group History Statistics on an Interface (optional)

•Collecting Group Ethernet Statistics on an Interface (optional)

Default RMON Configuration

RMON is disabled by default; no alarms or events are configured.

Only RMON 1 is supported on the switch.

Configuring RMON Alarms and Events

You can configure your switch for RMON by using the command-line interface (CLI) or an SNMP-compatible network management station. We recommend that you use a generic RMON console application on the network management station (NMS) to take advantage of the RMON network management capabilities. You must also configure SNMP on the switch to access RMON MIB objects. For more information, see "Configuring SNMP."

Beginning in privileged EXEC mode, follow these steps to enable RMON alarms and events. This procedure is required.

To disable an alarm, use the no rmon alarm number global configuration command on each alarm you configured. You cannot disable at once all the alarms that you configured. To disable an event, use the no rmon event number global configuration command. To learn more about alarms and events and how they interact with each other, see RFC 1757.

You can set an alarm on any MIB object. The following example configures RMON alarm number 10 by using the rmon alarm command. The alarm monitors the MIB variable ifEntry.20.1 once every 20 seconds until the alarm is disabled and checks the change in the variable's rise or fall. If the ifEntry.20.1 value shows a MIB counter increase of 15 or more, such as from 100000 to 100015, the alarm is triggered. The alarm in turn triggers event number 1, which is configured with the rmon event command. Possible events can include a log entry or an SNMP trap. If the ifEntry.20.1 value changes by 0, the alarm is reset and can be triggered again.

Switch(config)# rmon alarm 10 ifEntry.20.1 20 delta rising-threshold 15 1 
falling-threshold 0 owner jjohnson

The following example creates RMON event number 1 by using the rmon event command. The event is defined as High ifOutErrors and generates a log entry when the event is triggered by the alarm. The user jjones owns the row that is created in the event table by this command. This example also generates an SNMP trap when the event is triggered.

Switch(config)# rmon event 1 log trap eventtrap description "High ifOutErrors" owner 
jjones

Collecting Group History Statistics on an Interface

You must first configure RMON alarms and events to display collection information.

Beginning in privileged EXEC mode, follow these steps to collect group history statistics on an interface. This procedure is optional.

To disable history collection, use the no rmon collection history index interface configuration command.

Collecting Group Ethernet Statistics on an Interface

Beginning in privileged EXEC mode, follow these steps to collect group Ethernet statistics on an interface. This procedure is optional.

To disable the collection of group Ethernet statistics, use the no rmon collection stats index interface configuration command.

This example shows how to collect RMON statistics for the owner root:

Switch(config)# interface gigabitethernet0/1

Switch(config-if)# rmon collection stats 2 owner root

Displaying RMON Status

To display the RMON status, use one or more of the privileged EXEC commands in Table 25-1:

For information about the fields in these displays, see the "System Management Commands" section in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2.